1. Field of the Invention
The invention relates to an inkjet-recording method and an inkjet-recording material favorable for recording of a photograde image allowing long-term storage.
2. Description of the Related Art
In recent years, with the rapid progress in the communication industry, various information-processing systems have been developed, and various recording methods and devices suitable for use in these information-processing systems have also been developed and implemented in practice. For example, inkjet-recording methods have become widely used, because inkjet methods allow printing on various recording materials, and the hardware (devices) thereof is relatively cheaper, more compact, and more silent.
Recently, it is possible to obtain so-called high quality photographic-like image recording media, and the important properties required for such media include (1) high drying speed, (2) suitable and uniform ink dot diameter (without ink blurring), (3) favorable graininess, (4) high circularity of ink dot, (5) high color density, (6) high color saturation (without dullness), (7) favorable light and water resistance in recording portions, (8) high whiteness of recording sheet, (9) favorable shelf life of the recording sheet (without yellowing or image blurring during long-term storage), (10) favorable dimensional stability (low curling), (11) favorable operation of hardware, and the like.
However, even when a recording medium satisfies the requirements of the various properties above, if the recorded image is inferior in weather resistance, for example, to light or ozone, images can not retain their high quality, leading to a decrease in the commercial value as a recording material. Thus, it is important for a recording material to give a photographic image quality and also to be capable of maintaining the recorded photographic image for an extended period of time.
Widely known as inkjet-recording media are recording materials prepared by coating a pigment containing a silicon compound, such as silica, and a water-based binder together on a paper substrate.
Metals, metal ions or metal salts have been used for improvement in light stability and color reproducibility and prevention of image blurring and beading, and, for example, there are disclosures on the methods of using a bivalent or higher metal ion or salt, a polyvalent metal cation, or a water-soluble polyvalent metal (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 10-100531, 11-321094, 2002-96547, and 2002-264485).
On the other hand, dyes are more susceptible to discoloration by gas, such as ozone, or light than pigments commonly used as colorants, and the image recorded with dye is known to show deterioration during long-term storage.